Open Source Speech Software

Transform pure innocent audio files, speech, music, etc into unholy demonic abominations. Audio Satanifier 666 is a fun easy-to-use browser-based tool forged in the pits of hell, for voice actors, musicians, sound designers, for memes, for creative projects or anyone else who want to twist their sound into something absolutely diabolical! Layperson friendly - you'll be able to apply cool effects to your audio file even if you know nothing about audio engineering. Theres also a Mini version that has a voice deepening that doesn't slow the speed of the audio. Its more focused on the "satan voice" filter, while the larger default version has 16 different filters you can mix and match. (Source code is included within the html file itself.)

Audacity Policial (aka Audacity Police) is an extension of Audacity sound editor that was created to help police and justice investigations based on phone call and environmental recordings, supporting audio analysis and transcription.

A XFig based rapid prototype yeilding an audio speed alteration tool. This tool lets you arbitrarily alter the speed of audio files. It uses the WSOLA algorithm for audio speed alteration without pitch change.